I. Field of the Invention
The present invention relates to an electro-surgical instrument used for making incisions in tissue in which the blade is made to vibrate during use at a predetermined amplitude and frequency. The rapid, imperceptible movement of the blade results in cavitation at the blade'surface which frees it of the buildup of organic debris. More particularly, the present invention relates to a unique blade construction and blade holder for use in connection with such a tool.
II. Discussion of the Prior Art
As described in applicant's patent application Ser. No. 756,248 filed on July 18, 1985, now U.S. Pat. No. 4,674,498, various prior art electro-surgical blades have been less than effective since those blades either must be made of a special material, or must carry a considerably higher voltage which may cause undue tissue damage. Other prior art devices do not allow for proper coupling of the blade member to the voltage source and, therefore, tend to be ineffectual. Still other prior art blade and holder assemblies have extremely elaborate and complex electrical circuits which fail to accomplish a desirable result of an effective electro-surgical tool capable of operation in more than one mode.
One of the most severe problems in the prior art is the adhesion of charred tissue and blood to the blade which uncontrollably and erratically alters the impedance between the two blade energizing conductors and, therefore, renders the instrument almost useless as an effective cutting and/or electro-cautery device. The present invention provides an electro-surgical tool which, by utilizing state of the art semiconductor or printed circuit masking technology, can be designed to function as a standard surgical blade or as an electrified blade for cutting tissue and coagulating blood. The present invention also provides surgeons with an electro-surgical tool which can be used with either a capacitive blade or a resistive blade. The invention further provides means for locking either of the foregoing type of surgical blade in place with respect to a handle and for vibrating the blade so as to produce the desired cavitation effect for cleansing the blade continuously during use.